Conventionally, a circuit breaker that is installed in an electrical power stations such as a substation and a switching station to interrupt a current has been used. In some cases, a double-break circuit breaker having two arc-extinguishing chambers that extinguish an arc occurring between contact makers and interrupt a current is used as the circuit breaker. The circuit breaker having two arc-extinguishing chambers is also referred to as “double-break circuit breaker” in the following explanations. The double-break circuit breaker has an advantage such that an operation force required at the time of interrupting a current is smaller than that of a single-break circuit breaker.
In the double-break circuit breaker, a first arc-extinguishing chamber, connection conductors, and a second arc-extinguishing chamber are arranged horizontally in a line along a tank shaft center as described in Patent Literature 1, for example. A portion of the connection conductor is supported by an insulating support tube. An operation device for operating the circuit breaker is arranged under the insulating support tube.
Furthermore, Patent Literature 2 discloses a double-break circuit breaker in which two breaking units connected with a bracket are accommodated in one hermetic container. The bracket is supported by a support insulator, and an internal conductor has a V-shape as a whole.